Process for making fenders



1952 D. J. DUNLOP 2,606,517

PROCESS FOR MAKING FENDERS 2 Sl-lEETS SHEET 1 Filed Aug. 31, 1949 S-nvcmor @wacmw 72 f 5 I Gttomup Patented Aug. 12, 1952 PROCESS FOR MAKING FENDERS David James Dunlop, Pontiac, Mich., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application August 31, 1949, Serial No. 113,373 7 Claims. (01. 113-1l6) This invention relates generally to deep drawn sheet metal articles, and particularly to an improved method for making such articles in one piece from flat stock.

While the invention is applicable to the forming of various articles from sheet metal and the like where a relatively deep draw is required, it is particularly advantageous in the forming of automotive front fenders which incorporate an opening in the front Wall for the headlight, and I have chosen such an embodiment for purposes of illustration.

One aspect of the trend in modern automotive vehicle design has been to raise the crown of the front fenders to a height more and more nearly equal to that of the vehicle hood. This has resulted in greater extensions of the skirt and front wall sections of the fender to maintain the same shielding coverage of the wheels, which in turn necessitates a deeper draw of the metal to form the fender in one piece from a flat blank. As is well known in this art, the deeper the draw required the greater tendency there is for the metal to wrinkle and tear during the forming operation, with resultant increased labor and expense required in the finishing operation. Further, the greater forces applied to the metal in making deep drawn articles requires that larger blank holding portions must be provided, which are trimmed ofi as waste material after the drawing operation.

It is the object of my invention to provide an improved method for making so-called deepdrawn vehicle fenders and the like which substantially reduces the depth of draw required to obtain the shape and form desired.

My improved method contemplates the formation of a generally fiat blank of suitable size and. contour having a notch or gore extending inward from one edge in the section of deepest penetration by the draw punch, bending the blank into a dished, such as substantially cone or partial cone shape and welding or otherwise securing together the marginal edges of the notch, and then placing the dished blank between dies and drawing it to final shape. The notching of the blank and pre-forming it to a dished shape before the drawing operation makes the blank conform much closer to the shape of the draw die than it would if flat, and consequently the amount which the metal needs to stretch in assuming its final shape is considerably less. In applying my invention to the forming of front fenders for automotive vehicles which are to have an opening in the front wall for a headlight, the notch 2 is preferably located in the section of this opening so that thesubsequent removal of material for that purpose will eliminate a substantial portion of the notch seam in the finally completed fender.

In the drawings:

Figure 1 is a perspective view of a fiat sheet from which the portion shown in broken lines is stamped out to provide a blank for making an automotive vehicle front fender, a notch being provided in one end of the blank in accordance with my invention.

Figure 2 is a perspective view schematically showing suitable apparatus for effecting the bending of the flat blank of Figure 1 first into the V shape shown in Figure 3 and thence into the conical shape of Figure 5.

Figure 3 is a perspective View of the blank after, being bent to V shape along a longitudinal axis which passes through the vertex of the notch.

Figure 4 is a plan view of a portion of the apparatus of Figure 2, showing the operational step of bringing together the edge portions of the notch to obtain the partially conical shape of the blank shown in Figure 5.

Figure 5 is a perspective view of the blank after the edge portions of the notch have been brought together and welded in overlapping relation, causing the blank to assume a generally conical shape.

Figures 6 and '7 are transverse and longitudinal section views of the final stamping operation as performed in the draw die.

Figure 8 is a perspective view of the formed fender after removal from the draw die.

With more particular reference to the drawings, it will be seen that my improved method as applied to the making of an automotive vehicle front fender begins with the cutting out of a flat blank I shown in broken outline in Figure 1 from a flat sheet 2. The size and shape of this blank will of course, depend on the design of the particular fender to be made, it being considered necessary in this respect only to point out the front section 3 is made somewhat wider than is conventional and has a generally V-shaped notch: A in its forward edge 5. The provision of this notch is essential to my invention, and while it may be located otherwise than as shown, its location as illustrated is preferred for reasons which will be pointed out hereinafter. As shown, the notch 4 is disposed symmetrically of a generally longitudinal axis X of the blank, I, which axis will constitute the so-called crown line of the finally completed fender. 'The edges .6 and- 1 which define the notch are substantially the same length and both intersect the axis X at point 8 which constitutes the vertex of the notch and the apex of the cone or partial cone into which the blank is subsequently shaped. Preferably one edge e. g. 6 is cut straight throughout its length while the other edge I angles off rearwardly just short of the vertex point 8 as shown at 9 to provide for a generally uniform width of overlap by the notch edges 6 and 1 when the portions of the blank adjacent these edges are, subsequently bent into a partial cone shape.

The blank I is then pre-formed to the generally conical shape shown in Figure 5, wherein the notch 4 which formerly existed is now closed up by the edges 6 and I thereof having been brought together into overlapping relation and permanently thus secured as by weldin at I0. While this operation may be accomplished in various ways and in either one step or several steps, I havefound it'preferable to. carry itv out in a manner. which will now be described. I first bend'the blank: into. a. v-shape as shown in Figure 3, the bend line H being coincident with the axis X previously referred to, then force the front portions 3' and 3" on opposite sides of the bend line H toward each other until the notch edges 6. and l overlap, and finally weld these overlapping edges together as shown at min Figure 5. These 'operations-couldbe carried out by hand, of course,

or the bending of the blank to the V-shape of Figure 3 could be performed on a standard sheet metal break and the remaining operations completedzby hand.

In. Figures. 2 and 4 is schematically shown an apparatus which has provenveryconvenient for effecting this conical pre-forming; of the blank in massproduction. This consists essentially of a die frame or blockl 5' which is longitudinally-movable: oni guides indicateclby the ways It and IT toward and. away from a stationary die bloc: I8 by any power means such asan air cylinder not shown. The: upper face I9. of the movable block I55. is. trough or V-shaped to providea depression into which the flat fender blank may be forced to. effect the bending of the latter alongthe axis X (line II- in Figures 3-5). Downward pressure onthe; flat; blank is. effected-by an arm 20 which is also movable by suitable power m ans not shown, this arm 20 being schematically shown as a plate h nged at: 2. to the bl 5 alon one side. ed e f e. la rs r haped upp r fa e When the arm or plate 29 is swung from its-position as shown in solid lines to-its broken line position in Figure 2, its free edge 22 forces the blank to bend along the axis X. Any suitable holding means, such as the dowel pins indicated in broken; lines at 23 and 24 which project upwardly from-the block I 5 to engage holes provided therefor in one side of the 'blank, may be employed to anchor one, side of the blank to, insure uniform location of the bend line II. Figure 3 shows the shape of the blank after the operation just described.

While the blank isstill in the block I 5 and after. the arm 20 hasv been returned to its upra-ised position shown in Figure 2 the block I5 is moved toward the stationary die block I8 to effect. the closing of the notch 4 by bringing the notch edges 6 and I. into overlapping relation. D ringthis movement of the block I5, the end we l 2.5 abu the rear edge of the blank to insure its concurrent movement toward the stationary die. block I 8 This latter block isprovided with a, conically shaped face, 26. which serves to cam the blank end portions 3 and 3" into notch closing relation as the blank is forced toward the same by the die block I5. The portion of the die face 26 which receives the blank end portion 3 is offset slightly from the portion which receives the blank end portion 3" in order to insure that the notch edges 6 and I of the blank will overlap properly when they come together as will be clear from the plan view shown in Figure 4.

While the blank is still in the block I 5 and the end portions are held in notch closing position asshown in Figure 4, the edges 6 and I are welded together. The interior of the bent-up blank is accessible forone of the welding electrodes, and a slot 2-! which is provided in the stationary block I8 allows access for the other electrode. These electrodes, which are not shown, may be of any desired type. Figure 5 shows the blank as completely pre-formed preparatory to the draw die operation. It will be understood that in the operations thus far described no drawing or stretching of the. blank. hasbeen required, other than that locally associated with. its being bent along the line I I.

The dished shape obtainedv during the. preforming operations enables the blank to more closelyconform with the shape of the draw die and punch than does a flat blank, thereby reducing the amount of draw necessary to: effect the desired final shape of the blank shown in Figure 8.

Referring to Figures 6 and 7, numeral 30 represents a draw die and 3.! is the punch which cooperates therewith in the usual manner. Associated with and surrounding the punch 3i iathe blank holding member. 32-, which cooperates, in abutting relation with the outer marginal upper face. 33 of the, draw die prior to the advancement of the punch and holds the blanks marginal edge portions during the draw. Also shown is the ejector 3.4 which is reciprocably mounted in the draw die opposite the punch and actuatable as by the. air cylinder 35 to force the completed stamping out of. die upon withdrawal of the punch. 36-. 3'! and 38 are projecting hardened inserts carriedby the blank holder which depress the blank marginal edge portions into cooperating grooves provided. therefor in the upper face of the die block, further insuring against slippage of the blank relative to the blank holder during the draw.

The blank I is shown in solid section lines between the working surfaces 39 and d0 of the pun-ch and die, respectively, the shape which it assumes following the draw being clearly evident. The broken outline 4| in Figures 6 and 7 represent the longitudinal and transverse sectional configurations of the blank in its preformed condition of Figure 5, prior to the start of the draw die operation. The spacing between this broken outline II and the fully drawn blank I clearly demonstrates the considerable reduction in depth of draw required by my method over that which would result from drawing the fender from the conventional fiat blank.

T, T, T" and T in Figurest and 7 indicate the location of the trim lines at which the blank I is. trimmed of excess metal fOllOWiIlg its removal from the draw die. It will be noted that these trim-lines, particularly those designated T, 'I and T, are relatively close to the marginal extremities or edges 5, 42 and 43 of the blank, and that there is thus only a relatively narrow section of material which is trimmed off as scrap material. One of the factors responsible for this small amount of trim scrap is that the conically pre-formed blank of Figure possesses the necessary shape at its marginal edge portions to substantially conform to the marginal upper face 33 of the draw die prior to the drawing operation, which enables the use of a portion of the usable fender section of the blank adjacent the trim lines for blank holding purposes. One example of this condition is clearly apparent in Figure 6 wherein the :portion d5 of the blank inwardly of the trim line T is shown disposed opposite the blank holder 32. Another factor, is of course the reduced amount of draw required by reason of the substantial extent of uniformity of the dished shape blank to the draw die and punch, which in turn requires less force to effect the draw and consequently a smaller gripping area on the blank for the blank holder.

The notch 4 is preferably located in the forward edge 5 of the blank as earlier described where the completed fender is to house a headlamp having its lens opening 50 in the front wall 5|, since the latter opening will eliminate the upper and substantially greater portion 52 of the welded seam 53. The headlamp lens opening 50 is preferably formed subsequently to the draw die operation, employing any suitable blanking means for the purpose. Other locations for the notch 4 could be made, such as on either side and near the front of the fender within the scope of my invention. The most important factor in the location of the notch is that it be in a section of the fender where the greater portion of the draw is normally to occur.

Further, while I have described my invention with specific reference to the forming of automotive fenders, the principles thereof are applicable to the formin of any so-called deepdrawn article.

I claim:

1. A method of forming a drawn hollow sheet metal unit which would normally require a deep draw or a plurality of drawing operations from a single flat metal blank, comprising the steps of notching the blank inwardly from one edge, said notch extending into the area to be drawn, bending the blank to bring the edges of the notch together to form a dish-shaped article having its apex coincident with the vertex of the notch, securing the edges of the notch together by integral joining means of suflicient strength to prevent rupture during the subsequent drawing, and then drawing said article into the desired shape of the hollow metal unit.

2. The method of claim 1, including after notching, bending the blank into a V-shape about an axis extending through the vertex of the notch.

3. The method of claim 1 as applied to the forming of a vehicle fender having generally vertical walls depending from a top wall, wherein the notch is formed in the section of the blank which is to constitute a vertical wall of the fender.

4. The method of claim 1 as applied to the forming of a vehicle fender having end and side wall portions depending from a top wall portion, wherein the notch is formed in the section of the blank which is to constitute an end wall portion of the fender.

5. The method of claim 1 as applied to the forming of a vehicle fender having end and side Wall portions depending from a top wall portion, wherein the notch is formed in the section of the blank which is to constitute an end wall portion of the fender, and including the step, after drawing, of cutting an opening in said end wall portion displacing a portion of said joined edges.

6. The method of claim 1 as applied to the forming of a vehicle fender having end and side wall portions, wherein the notch is formed in the section of the blank which is to constitute an end wall portion of the fender, and including the step, after notching, of bending the blank to a V-shape about a longitudinal axis extending through the vertex of the notch.

7. The method of claim 1 as applied to the forming of a vehicle fender, including after notching, bending the blank longitudinally through the notch by moving the marginal edge portions of the blank on opposite sides of the blank into substantially the angular relation which said portions bear to each other after the draw step.

DAVID JAMES DUNLOP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 939,714 Kowarsky Nov. 9, 1909 1,399,951 Forysth Dec. 13, 1921 1,540,572 Schroder June 2, 1925 1,724,894 Batie Aug. 20, 1929 2,166,266 Behko July 18, 1939 2,556,738 Peterson June 12, 1951 FOREIGN PATENTS Number Country Date 226,971 Switzerland Aug. 2, 1943 

